Typewriter ribbon and ink composition therefor



Dec. 28, 1937. w, sc 2,103,275

TYPEWRITER RIBBON AND INK COMPOSITION THEREFOR Filed Nov. 22, 1934Patented Dec. 28, 1937 UNITED STATES TYPEWRITER RIBBON AND INK COMPOSI-TION THEREFOR George W. Schaefer, Quincy, Mass. Application November 22,1934, Serial No. 754,312

8 Claims.

A subject of this invention is a typewriter ribbon such as may serve invarious machines wherein type or printing elements are caused to pressor strike against the ribbon and efiect a transfer of the printingmedium carried by the ribbon in the form of letters, numbers, andvarious other signs or indicia against a paper or other base designed toreceive the imprint or impression of the type or printing elements.Accordingly, the expression typewriter ribbon" as used in the followingdescription of my invention and in the appended claims is intended tocomprehend a ribbon such as may be employed in typewriting machines,adding machines, multigraph machines, billing machines, addressegraphmachines, dupligraph machines, or other machines that operate withpermanent typing or printing elements or with removable printing platesor other typing or printing members. Another subject of this inventionis theprinting medium or ink composition that is adapted to serve as anessential part of the typewriter ribbon of the present invention.

Typewriter ribbons as heretofore made are impregnated substantiallyuniformly throughout with a printing medium so that the printing mediumoccurs both on the face that contacts with the typing or printingelements as well as on the face that contacts with the paper or otherbase to which the printing medium is transferred by reason of pressureor impact exerted by the printing elements on the ribbon. Ribbons somade present the serious fault that the printing elements become soiledwith the printing medium, in consequence of which the printing elementstend to become so fouled with the printing medium that the desireddistinctness or sharpness of imprint ,or impression is not realized.Thus, in the case of such machines as typewriters, unless the type isfrequently cleaned, it may become so badly fouled with printing medium,that blurred or indistinct impressions result. In the case of removableprinting members, such as the printing plates used in dupligraphmachines, addressograph machines, and department store charge-platemachines, although such members may be used so infrequently as not toimpair the distinctness or sharpness of the imprint secured therefrom,nevertheless, inasmuch as the operator handles such removable members asthey are inserted in and removed from such machines, the operators handsare likely to become soiled with the thin film of printing medium thatremains as a residue on such members and on their printing elements andaccordingly result in the soiling of. the imprinted paper forms that theoperator also handles at the same time.

A prime objective of the present invention is the provision of atypewriter ribbon that will function to transfer printing mediumperfectly and for a long period of time to a paper or other base underthe pressure or impact of type or printing elements in machines of theclass already mentioned without, however, depositing any sensible orsignificant amount of printing medium on the type or printing elements.Generally stated, the typewriter ribbon of the present inventioncomprises the usual fabric base carrying on only one face thereof acoating of transferable printing medium of such character andconsistency that it is readily transferred under the usual pressure orimpact of type or printing elements to a. paper or other suitable basewhile at the same time having substantially no tendency to migrate orbleed to the uncoated face of the fabric base. The coated face of theribbon is, of course, the one that is to be brought next to the paper orother base to -receive the imprint or impression, whereas the uncoatedface of the ribbon is the one that is to receive the pressure or impactof the printing elements. Accordingly, the printing elements do notcontact with the printing medium and are thus preserved in a cleancondition conducive to perfect imprint or impression. The coatlngofprinting medium carried by the typewriter ribbon of the presentinvention is further characterized by its goodkeeping quality, that is,its remaining unspoiled for a long period of time, by its substantialuniformity or even distribution over the ribbon surface, and by itsextreme thinness, all of which qualities are necessary in attaining goodimpressions or clear imprints from the ribbon over a long period oftime. 'Despite the extreme thinness of its coating of printing medium,the ribbon is further characterized by its. high printing capacity, thatis, its ability to give a large number of imprints and thus afford longservice.

Although'the printing medium constituting the coating on the typewriterribbon of the present invention contains as ordinarily carbon black orother pigment particles of the desired color, unlike the printing mediaof typewriter ribbons as heretofore made, its pigment particles are keptproperly lubricated and in a weakly aggregated or bonded condition by asoap binder which carries substantially uniformly entrained or dispersedtherethroughout the oil necessary for effecting such lubrication. that:various kinds of soaps, including sodium and potassium base soaps ofvarious fatty acids, such as palmitic, stearic', etc., might be used asthe soap binder for maintaining the desired weakly aggregated or bondedcondition of the pigment particles in the coating of the typewriterribbon of the present invention, I prefer to use theammonium soaps andmore especially ammonium oleate for this purpose, as I have found thatthe desired weak bonding or aggregating action on the pigment particlesin the coating is had through the use of the ammonium soap and moreespecially ammonium oleate while at the same time substantially avoidingany stickiness or tackiness in the coating. 80, too, while variousoleaginous liquids may serve for lubricating the pigment particles so asto promote ready transfer or parting of such particles from the ribboncoating to a paper or other base, including many mineral, vegetable, andanimal oils, I may to advantage employ oleic acid as the lubricant, foroleic acid is comparatively inexpensive, has the desired lubricatingquality, and can be readily and perfectly introduced as the lubricatingelement of the printing medium at the very same time that the ammoniumoleate soap is being produced therefrom as the weak or loose binderelement of the printing medium. a

I shall now give a specific example of procedure leading to a typicalprinting medium or ink composition such as I may advantageously employas the coating on the typewriter ribbon of the present invention. To asuitable mixing or kneading machine, such as a Werner and Pfleiderer orDay mixer, is added four parts of lampblack or other suitable pigment,depending on the color of imprint desired to be had from the ribbon.When lampblack or other carbon black is the pigment employed, it ispreferable to add to such pigment two parts of graphite. The graphiteplays the role of both a pigment and a lubricant. The pigment charge isthen subjected to the mixing or kneading action of the machine and,whfle such action is taking place, the pigment charge is treated withone-half part of oleic acid containing preferably a few drops of anessential oil, like oil of sassafras, that masks any malodor that may beassociated with the oleic acid. After the pigment particles have beensubstantially uniformly wet or treated on their surfaces with the oleicacid, which result may require about fifteen minutes, ammonia water isadded to the charge in amount designed to effect only a partialsaponification of the oleic acid, that is, a saponification that windsup with considerable free or residual oleic acid dispersed throughoutthe charge. After considerable experimentation, I have found that it isdistinctly preferable to add the ammonia water gradually to the chargeas it is being mixed, since if the ammonia water is added all at once,the tendency is to form a discontinuous or granular mass from which thefree oleic acid is apt to separate on the surface as large or visibledrops of oil whereas, when the ammonia water is added gradually, thecharge remains continuous and the resulting composition is one ofsubstantially uniform consistency throughout which the free oleic acidis so finely dispersed that not even tiny oil particles appear therein.I have established empirically that when one-quarter part of ammoniawater of 26% strength is gradually added to the mixed charge of pigmentand oleic acid over a period of about four to five minutes, theresulting composition aioaavs contains ammonium oleate and free oleicacid in the desired proportions and state of interspersion and has aconsistency nicely adapted for application to a typewriter ribbon fabricbase. It should be observed that volumetric proportions of the variousingredients are hereinbefore 'given and that mixing of the ingredientsis effected under prevailing room temperature, that is, without theapplication of heat. It should further be noted that upon the additionof the ammonia water to the charge, the charge undergoes a small rise intemperature on account of the heat evolved by the saponiflcation of theoleic acid. A considerable fraction of the ammonia present in theammonia water is volatilized and lost during the mixing operation byreason of the volatility of the ammonia and the increased tendency toexpel ammonia under the heat of the saponifying reaction.

Upon completion of the saponifying reaction in the mixer, the reactionproduct or resulting printing medium or ink composition is asubstantially uniform and continuous mass of a moldable, stiff,putty-like consistency. It is readily and smoothly smearable underpressure and deposits a substantially uniform but extremely thin coatingon a fibrous surface, such as the surface presented by the usualtypewriter ribbon fabric base. Before being applied to such a base,however, the composition is preferably molded into small cakes or cubes.The molding of the composition into cake or cube form is preferably doneimmediately upon its being removed in freshly prepared condition fromthe mixer. Inasmuch as the resulting cakes or cubes are still moist orwet with the water added as ammonia water to the mixer and inasmuch asthe water detracts from the smoothness of smearability of thecomposition, it is preferable to dry the cakes before composition issmeared therefrom onto a typewriter ribbon fabric base. Drying of thecakes may be effected as by allowing them to stand under roomtemperature conditions for about twenty-four hours, assuming, forexample, that the cakes are about 1%" long, about 1" wide, and thick. 7It is, of course, obvious that cakes of various dimensions might beformed, depending upon the width of the ribbon to be treated therewith,and that the particular time of drying in a particular instance dependsupon the particular dimensions of the cakes to be dried. In someinstances, it may be desirable to mold cakes or cubes of a widthsomewhat greater than that of the typewriter ribbon fabric base so thatwhen a cake is pressed down on such base, as the base is being movedrelative to the cake, the entire surface of the base will becomesubstantially uniformly smeared with the composition. As alreadyindicated, such an operation results in the deposition or transfer of anexceedingly thin coating of composition onto the base; and thecomposition is both firmly adherent to the base and does not tend tostain or bleed through the base to any significant extent even thoughthe uncoated surface of the base is subjected locally to the repeatedpressure or impact of the usual type or printing elements. Evidently,the free oil component of the composition is largely dispersed in andheld entrapped by the soap component of the composition and so is freein a chemical sense to lubricate the pigment particles but not in amechanical sense to escape through the fabric base. Indeed, the coatedface of the ribbon does not readily part with the composition, insomuchthat the typewriter ribbon carrying the coating may be convoluted ontoitself into roll form without causing the coated face of one convolutionto soil to any appreciable extent the uncoated face of the adjacentconvolution. In other words, it is only when printing pressure or impactis received by the ribbon, and more particularly by its uncoated face,that it. tends to part with the composition or printing medium andtransfer it to the paper or other base against which the coating iscaused to press or strike.

Typewriter ribbons made in accordance with the present invention may berestored to the desired fresh or initially effective condition, afterthe coating of printing composition or printing medium thereon hasbecome depleted or exhausted, by smearingthe printing surface thereof,as hereinbefore indicated, with the composition applied under pressurefrom a cake or cube. Such cake or cube may, in fact, be a permanentfixture or adjunct in the machine in which the ribbon is employed, thecake being constantly pressed against the printing surface of the ribbonas the ribbon is moving therepast. Thus, for example,

a typewriter machine may be equipped with such a cake at the region ofthe machine where the typewriter ribbon is being led into the wind-upcartridge from the zone of -action of the type, the

face at the same high effectiveness at all times.

If desired, only the central longitudinal zone of the ribbon, that is,its active zone, may be thus replenished with printing medium from acomparatively narrow cake serving as one of the machine fixtures. When amulticolor'ribbon is being used, the differently colored zones mayreceive printing media of the appropriate colors from two or moreindependent cakes, each cake smearing inking medium of the appropriatecolor on each color zone of the ribbon. Machines other than typewritermachines may be similarly equipped with one or more cakes of printingmedium.

It should be understood that I have hereinbefore described my inventionin specific terms that admit of variation and modification. Thus,instead of using oleic acid as the lubricant for the pigment particles,it is possible to use suitable unsaponifiable oil, such as the mineralor hydrocarbon oils, for this purpose, the unsaponifiable oil beingblended in suitable amount with the oleic acid and the oleic acid beingsaponified with the ammonia to completion so as to disperse and entrapthe unsaponifiable oil in the resulting ammonium oleate. So, too, it ispossible to vary the sequence of mixing the various ingredients that goto make up the resulting printing medium or ink composition, but I havefound it distinctly advantageous to carry out the steps in the orderhereinbefore given in arriving at the most satisfactory composition withminimum difllculties. In any event, the proportions of pigment, oil, andammonia or other alkali employed are'such as to conduce to a continuousmass of stiff, puttylike consistency and capable of being smeared underpressure readily and smoothly on a typewriter ribbon fabric base as a.thin substantially uniform coating having substantially no tendency tostain through the fabric base or onto another surface by mere contacttherewith but being transferable in small but sufficient amount to paperunder printing pressure and impact. Genbase.

erally stated, the pigment particles are by far the preponderantingredient of the coating, the soap binder being present incomparatively small amount and even a smaller amount of free oilimparting ample lubrication to the pigment particles. Although theprinting medium or ink composition of the. present invention might beapplied to paper or other transfer media or even to both faces of atypewriter ribbon fabric base, it is especially valuable for coatingonly one faceof a typewriter ribbon fabric base, since it possesses themany important advantages already mentioned for this particular use.

On the accompanying drawing,--

Figures 1 and 2 illustrate diagrammatically and conventionally how theprinting medium may be applied by hand. to a typewriter ribbon fabricFigure 3 is a section through the coated ribbon. Figure 4 similarlyshows apparatus for applying 2 the printing medium.

Figure 5 depicts a conventional cartridge or roll of the typewriterribbon of the present invention.

As shown in Figure l,'a small cake I of the printing medium may bepressed onto the usual typewriter ribbon fabric base H as either theribbon is being moved past the cake orthe cake is being moved over theribbon. Only a fragment ofribbon appears in the drawing, but it will beunderstood that a full length ribbon is being subjected to suchtreatment. The fabric base is preferably the usual thin, finely woven,

, and highly flexible fabric of low porosity containing yarns -of silk,Sea Island, Egyptian or other high gradev cotton, linen,-or similarfibers used in typewriter ribbons for the purpose of getting clean-cutor nice impressions practically unaffected by the'woven pattern of thefabric. Once the ribbon has had a thin coating I! of the printing mediumsmeared thereon, it may be put to use, but, as shown in Figure-2, it ispreferable to act upon the coating with a brush I3 whose bristles aredense and extremely fine'and thus even out such surface irregularitiesor nonuniform thickness localities as may exist in the coating.

The same operations as are shown being done by hand in Figures 1 and 2are shown being performed by apparatus in Figure 4, according to which aribbon it may be progressively withdrawn from a roll l5, passed over abearing surface or table I6, be appropriately smeared with printingmedium from a cake l1 and then be brushed by a brush 18 as it isbeing'supported by the table, and finally be rewound as a roll IS. Thecake l1 and the brush l8 are each shown as being held by a holder 20equipped with a compression spring that maybe designed to exert therequisite working pressure on the cake and on the brush. v

A finished typewriter. ribbon 2| carrying a coating 22 on only one facethereof, in accordance with my invention, appears in Figure con-- 1. Aprinting medium especially adapted for application as a coating totypewriterribbons consisting of a continuous mass of stiff, puttylikeconsistency and smoothly smearable under pressure as a thinsubstantially uniform coating onto a typewriter ribbon fabric base, saidmass comprising pigment particles, a soap weakly bonding together saidparticles, and an oil lubricating said particles and finely dispersedthroughout and entrapped by said soap, said oil lubricant being presentin such small amount relative to said pigment particles as merely to wetor lubricate said particles and hence being substantially unavailable infree condition.

2. A printing medium especially adapted for application as a coating totypewriter ribbons consisting of a continuous mass of stiff, puttylikeconsistency and smoothly smearable under pressure as a thinsubstantially uniform coating onto a typewriter ribbon fabric base, saidmass comprising pigment particles, a comparatively much smaller amountof soap weakly bonding together said particles, and an oil lubricatingsaid particles and finely dispersed throughout and entrapped by saidsoap, said oil lubricant being present-in such small amount relative tosaid pigment particles as merely to wet or lubricate said particles andhence being substantially unavailable in free condition.

3. A printing medium especially adapted for application as a coating totypewriter ribbons consisting of a continuous mass of stiff, puttylikeconsistency and smoothly smearable under pressure as a thinsubstantially uniform coating onto a typewriter ribbon fabric base, saidmass comprising pigment particles, an ammonium soap weakly bondingtogether said particles, and an oil lubricating said particles andfinely dispersed throughout and entrapped by said ammonium soap, saidoil lubricant being present in such small amount relative to saidpigment particles as merely to wet or lubricate said particles and hencebeing substantially unavailable in free condition.

4. A printing medium especially adapted for application as a coating totypewriter ribbons consisting of a continuous mass of stiff, puttylikeconsistency and smoothly smearable under pressure as a thinsubstantially uniform coating onto a typewriter ribbon fabric base, saidmass comprising pigment particles, ammonium oleate weakly bondingtogether said particles, and an oil lubricating said particles andfinely dispersed throughout and entrapped by said ammonium oleate, saidoil lubricant being present in such small amount relative to saidpigment particles as merely to wet or lubricate said particles andparatively much smaller amount of ammonium oleate weakly bondingtogether said particles,

and free oleic acid lubricating said particles and finely dispersedthroughout and entrapped by said soap. I

6. A typewriter ribbon consisting of a thin, closely woven, highlyflexible fabric base having one face thereof coated with a transferablewriting medium made up largely of pigment particles and an oil lubricanttherefor, said all being present in such medium in small proportionrelative to said pigment particles and in amount sufilcient only tolubricate said particles and to provide an adherent coating penetratinginto said ribbon less than the full thickness thereof, whereby atransfer or writing face is provided on only one face of said ribbon.

7. A typewriter ribbon consisting of a thin, closely woven, highlyflexible fabric base having one face thereof coated with a transferablewriting medium made up largely of pigment particles, a soap weaklybonding together said pigment particles, and an oil lubricant for saidpigment particles, said oil being present in such medium in smallproportion relative to said pigment particles and in amount sufilcientonly to lubricate said particles and to provide an adherent coatingpenetrating into said ribbon less than the full thickness thereof,whereby a transfer or writing face is provided on only one face of saidribbon.

8. A typewriter ribbon consisting of a thin, closely woven, highlyflexible fabric base having one face thereozf coated with a transferableamount sufllcient only to lubricate said particles and to provide anadherent coating penetrating into said ribbon less than the fullthickness thereof, whereby a transfer or writing face is provided ononly one face of said ribbon.

GEORGE W. SCHAEFER.

